Surgery – Instruments – Means for removing tonsils – adenoids or polyps
Reexamination Certificate
1999-08-31
2001-05-01
Wilson, John J. (Department: 3732)
Surgery
Instruments
Means for removing tonsils, adenoids or polyps
Reexamination Certificate
active
06224611
ABSTRACT:
BACKGROUND OF THE INVENTION
The present disclosure relates to subject matter contained in Japanese Patent Application No. 10-259775 (filed on Sep. 14, 1998), which is expressly incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a snare that is inserted into an instrument-inserting channel of an endoscope to excise a polyp.
2. Description of the Prior Art
FIG. 5
shows a distal end portion of a conventional snare for use with an endoscope. In a flexible sheath
1
, a control wire
2
is axially movably inserted, and a snare loop
3
formed by an elastic wire is connected to the distal end of the control wire
2
through a connecting pipe
4
.
At the distal end of the snare loop
3
, a single elastic wire is bent back in a U-shape as shown in FIG.
5
. Alternatively, two elastic wires are inserted into a binding pipe (not shown) so as to be secured together therein.
By virtue of the above-described arrangement, the snare loop
3
projects from or withdraws into the distal end of the flexible sheath
1
in response to an operation of advancing or retracting the control wire
2
in the axial direction. When projecting from the distal end of the flexible sheath
1
, the snare loop
3
expands in a loop shape by its own elasticity. When pulled into the distal end of the flexible sheath
1
, the snare loop
3
is folded.
To excise a polyp with the snare, the base of the polyp is encircled with the snare loop
3
expanded by being pushed out from the distal end of the flexible sheath
1
. In this state, the control wire
2
is pulled toward the proximal end of the flexible sheath
1
(rightward as viewed in FIG.
5
).
Consequently, the snare loop
3
is gradually pulled into the flexible sheath
1
while reducing the loop size, causing the polyp to be pinched tight with the snare loop
3
. If a high-frequency electric current is supplied to the snare loop
3
through the control wire
2
in this state, the polyp is cut off without bleeding.
In the conventional snare for an endoscope having the above-described structure, however, the inner diameter d of the flexible sheath
1
must be larger than the outer diameter of the connecting pipe
4
, which connects together the control wire
2
and the two portions of the single elastic wire or the two elastic wires that constitute the snare loop
3
. In a case where the width W of the distal end portion of the snare loop
3
is larger than the outer diameter of the connecting pipe
4
, the inner diameter d of the flexible sheath
1
must be larger than the width W.
Consequently, the inner diameter of the flexible sheath
1
becomes considerably large. Therefore, when the control wire
2
is pulled to pinch a polyp tight with the snare loop
3
, the polyp may be undesirably drawn into the flexible sheath
1
. This may hinder the polyp excision treatment.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a snare for an endoscope that is designed so that a polyp pinched tight with the snare loop is unlikely to be drawn into the flexible sheath, and thus a polyp excision treatment can be performed safely and smoothly.
Other objects and advantages of the present invention will become apparent from the following detailed description of illustrated embodiments of the invention.
According to the present invention, there is provided a snare for an endoscope including a control wire axially movably inserted in a flexible sheath. A snare loop is formed by an elastic wire and connected to the distal end of the control wire. When the control wire is advanced axially, the snare loop projects from the distal end of the flexible sheath and expands in a loop shape by its own elasticity. When the control wire is retracted axially, the snare loop is pulled into the distal end of the flexible sheath and folded. The snare loop is formed by two elastic wires between two mutually secured portions of the elastic wires, which are laid in parallel and in close contact with each other and secured together directly at two positions longitudinally spaced apart from each other. The control wire is formed by an extending portion of at least one of the two elastic wires that extends rearward from one of the two mutually secured portions that is at the rear end of the snare loop.
REFERENCES:
patent: 4643187 (1987-02-01), Okada
patent: 5330482 (1994-07-01), Gibbs et al.
patent: 5376094 (1994-12-01), Kline
patent: 5496330 (1996-03-01), Bates et al.
patent: 5957932 (1999-09-01), Bates et al.
patent: 6013086 (2000-01-01), Ouchi et al.
patent: 5176941 (1981-11-01), None
patent: 56-160516 (1981-11-01), None
patent: 4-146743 (1992-05-01), None
patent: 8-224254 (1996-08-01), None
Asahi Kogaku Kogyo Kabushiki Kaisha
Greenblum & Bernstein P.L.C.
Robert Eduardo C.
Wilson John J.
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